Evaluation of Schlemm Canal Parameters Using Swept-Source Optical Coherence Tomography in Eyes That Underwent Keratoplasty

OBJECTIVES: In this study, we aimed to evaluate Schlemm canal parameters using anterior segment swept-source optical coherence tomography in eyes that underwent keratoplasty and compare them with keratoconus and healthy control groups. METHODS: The study included 32 patients who underwent penetrating keratoplasty or deep anterior lamellar keratoplasty once due to keratoconus and age-matched and sex-matched 20 keratoconus patients and 30 healthy controls. In all the patients, a single horizontal image centered on the central cornea was obtained from the nasal and temporal quadrants with low-intensity scanning to visualize Schlemm canal. RESULTS: There was no statistically significant difference between the groups for age and gender ( P ˃0.05). In the keratoplasty group, the area and diameter of Schlemm canal were 2.266±1.141μm 2 and 160.77±65.08 μm, respectively, in the nasal quadrant and 2.623±1.277 μm 2 and 158.81±68.05 μm, respectively in the temporal quadrant, which were statistically significantly lower compared with other groups ( P <0.001 for all). There was no significant difference between the penetrating and deep anterior lamellar keratoplasty subgroups for Schlemm canal parameters. CONCLUSION: This is the first study to report anterior segment optical coherence tomography after surgery shows SC parameters that are, on average, less than age-matched and keratoconus controls.